26 N. H. AGR. EXPERIMENT STATION. [Bulletin 157 



Cause of Winter Injury. The winter of 1906-1907 was an 

 unusually cold one and the low temperature might be regarded 

 as sufficient explanation for the serious results. Injury from 

 cold in plants, however, is largely dependent upon the condition 

 of the cells exposed. The fall of 1906 was characterized by the 

 frequency of showers and unusually high temperatures. As a 

 result of this, growth continued late in the season and the trees 

 must have gone into the winter without the usual reduction in 

 amount of water, and with the wood not completely matured. 

 This would be especially true of vigorous growing varieties like 

 the BaldAvin, and of trees situated on low ground and in poorly 

 drained soil. The apple crop of 1906 was large and the vitality 

 of the trees thus greatly reduced. This weakening from over- 

 production was probably also partly responsible for the injuries 

 of the following winter. 



Treatment. The great lesson to be learned from the winter 

 injuries that have occurred in the state is that of the importance 

 of air and soil drainage in the selection of an orchard site. Injured 

 trees have usually been benefited bj^ rather severe pruning. 

 The general occurrence of canker fungi in the state makes the 

 treatment of the injured areas of special importance. Like 

 all other wounds, they should be covered with wax or coated with 

 paint or Bordeaux. 



SPRAY INJURY. 



Injury from Bordeaux mixture is of quite common occurrence 

 in New Hampshire. On the leaves it appears first as purplish 

 brown spots of various shapes and sizes. They are usually 

 smaller, more irregular in shape and more thickly distributed 

 on the affected foliage than the leaf spot previously' described. 

 Soon after the appearance of these spots the leaves may begin 

 to turn yellow. Leaves so affected soon fall, and in serious cases 

 the trees may be almost entirely defoliated. Such extreme cases, 

 however, have been very rare. 



On the fruit the injury appears first as small, black or brown 

 specks scattered thickly over the apple. Later in the season 

 the skin may become corky and russeted. In serious cases the 

 apple may Vje much roughened and deformed, and large, deeply- 

 sunken scars develop (Fig. 30). The slightly affected fruit 



